Iodate, 221 table

Iodized Salt. Iodized table salt has been used to provide supplemental iodine to the U.S. population since 1924, when producers, in cooperation with the Michigan State Medical Society (24), began a voluntary program of salt iodization in Michigan that ultimately led to the elimination of iodine deficiency in the United States. More than 50% of the table salt sold in the United States is iodized. Potassium iodide in table salt at levels of 0.006% to 0.01% KI is one of two sources of iodine for food-grade salt approved by the U.S. Food and Dmg Administration. The other, cuprous iodide, is not used by U.S. salt producers. Iodine may be added to a food so that the daily intake does not exceed 225 p.g for adults and children over four years of age. Potassium iodide is unstable under conditions of extreme moisture and temperature, particularly in an acid environment. Sodium carbonate or sodium bicarbonate is added to increase alkalinity, and sodium thiosulfate or dextrose is added to stabilize potassium iodide. Without a stabilizer, potassium iodide is oxidized to iodine and lost by volatilization from the product. Potassium iodate, far more stable than potassium iodide, is widely used in other parts of the world, but is not approved for use in the United States. 

According to Table 11.4, Ksp = 5.0 X 10 6 for chromium(III) iodate in water. Estimate the molar solubility of the compound. 

A host of other pharmaceutical substances, namely cetrimide, hydralazine hydrochloride, phenylhydrazine hydrochloride may be assayed by titration with potassium iodate as mentioned in Table 13.3. 

TABLE 19.9. Solubility of Cupric Iodate in Aqueous Solutions of KCl at 25°C... 

Instead of the base chges listed in the table, the following other combinations may be used a)Combination of one of the powd metals, such as Zn, Cr, Cd, Fe, Co, Ni, Pb, Cu, As, Bi or Sb with oxidizers, such as permanganates, perchlorates, perborates, persulfites, peroxides, chlorates, bromates and iodates b)combination of Mg or A1 with cyanides, phosphates, carbonates, sulfates, etc... 

Potassium iodide and potassium iodate are commonly added to table salt to prevent iodine deficiency and associated thyroid disease. 

Detailed studies on the UV absorption spectra of alkenyl-A3-iodane 133 (X = Cl,Br,I) in acetonitrile solutions in the presence of tetrabutylammonium halides show the equilibrium formation of the iodate 134 (Sect. 2.1), in addition to the iodonium ion 132 coordinated by acetonitrile via hypervalent bonding. [Eq. (116)] [213]. The equilibrium constants are summarized in Table 5. Determinations of the equilibrium constants by UV spectra were carried out at a low concentration of the A3-iodane (<10 4 M), without considering the formation of the corresponding dimers. The magnitudes of the equilibrium constant K1 clearly decrease in the order Cl >Br >1, which reflects the differences in the stability of alkenyl-A3-iodane 133. 

Inspection of Table II shows that a variety of iodine products are formed with the iodine in several oxidation states. Thus fixation materials with iodine as complexed elemental iodine, iodide, and iodate, must be evaluated, and the solid fixation matrix selected must be able to accept a variety of materials. 

Iodine Compounds. Since contact with water is the most likely release mechanism in either of the terrestrial disposal operations, we initially screened iodide and iodate compounds on the basis of their solubilities. Tables III and IV present rankings of the low solubility iodides and iodates, respectively, with the least soluble at the top. 

Since we selected cement as our solidification matrix, it is also desirable to use an iodine compound which is resistant to hydrolysis. Tables III and IV also include solubility data for the hydroxide analogs of the low solutility iodides and iodates, respectively. 

Table 4. Component processes of the arsenite-iodate-chlorite oscillator and their rate laws1...

Table 6. Some mechanistic steps in the arsenite-iodate reaction...

The chlorite-iodate-arsenite oscillator was the first oscillating reaction discovered which is based upon chlorite chemistry. The BZ reaction and its relatives are bromate oscillators, while the BL and Briggs-Rauscher oscillators are iodate systems. The initial chlorite oscillator was rapidly followed by a large family of related systems58"60, which are summarized in Table 8. We note that while most of these systems contain an iodine species (I-, I2, IOf) as well as the chlorite, at least two iodine-free chlorite oscillators exist. 

C ) Chlorite-iodate-reductant. Oscillators 2, 7, 8 a, 9 a, 10 a, 11 and 12 of Table 8 are of this type. The requirements for a successful substrate appear to be that (M8) be thermodynamically favorable and relatively rapid while (M10) is slow. 

During the early 1970s researchers at Bell Laboratories studied these salts, both hydrated and anhydrous, because of their interest in the electrical, magnetic, and structural properties of the compounds. Syntheses were also studied and the results were compared with previously published results.82 83 Densities of all the anhydrous rare-earth iodates, derived from crystallographic data,83a are listed in Table 9.20. Extensive crystallographic data of these salts are also provided, as is a comparison with previous work cited in our earlier publication.2... 

Further work has been reported since 1980. Roy, Ghosh, and Nag84 have studied phase transitions for the iodates of La, Pr, and Nd. These are listed in Table 9.21. Note that S° for these compounds is not known. The thermal decomposition of hydrated La(I03)3 has also been studied.85 The final H20 is driven off at 250°C, and the iodate then decomposes to the periodate at 560°C ... 

The relationship between chemical composition of the oxidizer and the burning time of the sawdust has been determined by Uehara. The results are shown in Table 3.18. The trend in burning rate is tabulated as a function of the anion. The order of the burning rate of sodium salts is chlorite > peroxide > bromate > chlorate > nitrite > iodate > perchlorate > nitrate > bichromate. 

Iodates of Mnm are perhaps represented in the yellow to brown-yellow solids M2Mn(I03)5. There is also a range of isopoly- and heteropoly-anion compounds which we have summarized in Table 26. 

It will be appreciated that iodate is incompatible with both iodide (cf. Section IV.21, reaction 6) and with thiocyanate (Section IV.21, reaction 9) since iodine is liberated in acid solution. Also sulphide is incompatible with both bromate and iodate (oxidation to sulphate occurs), and an arsenite is oxidized by iodate in acid solution. These facts should therefore be borne in mind when interpreting Table V.30. An independent test for iodate (test 11) is provided below this can be performed before the silver nitrate tests. 

Disodium periodate, Na2HgI06, can be prepared by the action of chlorine on a mixture of sodium iodate and hydroxide,16 or by the oxidation of iodine with sodium peroxide.17 It is soluble with difficulty in both cold and hot water. The table gives determinations of solubility made by Rosenheim and Loewenthal 18... 

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